CVE-2024-39347
📋 TL;DR
This vulnerability allows man-in-the-middle attackers to bypass firewall protections and access sensitive internal network resources on Synology routers. It affects Synology Router Manager (SRM) installations with incorrect default permissions in firewall functionality. Attackers can potentially access intranet resources that should be blocked by firewall rules.
💻 Affected Systems
- Synology Router Manager (SRM)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access sensitive internal systems, steal data, or pivot to other network segments that should be protected by firewall rules.
Likely Case
Attackers with network access could bypass firewall restrictions to access internal web interfaces, file shares, or management consoles that should be blocked.
If Mitigated
With proper network segmentation and additional security controls, impact would be limited to the specific router's management interface and adjacent systems.
🎯 Exploit Status
Requires man-in-the-middle position. Unspecified vectors mentioned in advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: SRM 1.2.5-8227-11 or 1.3.1-9346-8
Vendor Advisory: https://www.synology.com/en-global/security/advisory/Synology_SA_23_16
Restart Required: Yes
Instructions:
1. Log into Synology Router Manager web interface. 2. Navigate to Control Panel > Update & Restore. 3. Check for updates and install SRM 1.2.5-8227-11 or 1.3.1-9346-8. 4. Reboot router after update completes.
🔧 Temporary Workarounds
Network Segmentation
allIsolate router management interface to separate VLAN or network segment
Access Control Lists
allImplement additional network ACLs to restrict access to router management interface
🧯 If You Can't Patch
- Implement strict network segmentation to isolate router management interface
- Deploy network monitoring and intrusion detection for unusual access patterns to internal resources
🔍 How to Verify
Check if Vulnerable:
Check SRM version in web interface: Control Panel > Info Center > DSM/SRM VersionCheck Version:
ssh admin@router 'cat /etc.defaults/VERSION'Verify Fix Applied:
Verify version is SRM 1.2.5-8227-11 or 1.3.1-9346-8 or later📡 Detection & Monitoring
Log Indicators:
- Unusual firewall rule bypass events
- Access to internal resources from unexpected sources
- Failed authentication attempts to internal systems
Network Indicators:
- Traffic patterns bypassing expected firewall rules
- Unexpected connections to internal services from router segment
SIEM Query:
source="synology-router" AND (event_type="firewall_bypass" OR dest_ip=internal_subnet AND src_ip=router_subnet)